Buffer for automatic firearms



March 7, 1961 F. HERLACH ETAL BUFFER FOR AUTOMATIC FIREARMS Filed Feb. 3, 1953 Fa in-J HERLA H R-Jrkl, UNDER lkelm S PALDING 'INVENTORS BUFFER FOR AUTOMATIC FIREARMS Friedrich Herlach, Friedrich Linder, and Wilhelm Spalding, Zurich, Switzerland, assignors to Machine Tool Works Oerlikon, Administration Company, Zurich- Oerlikon, Switzerland, a company of Switzerland Filed Feb. 3, 1958, Ser. No. 712,814

Claims priority, application Switzerland Feb. 8, 1957 2 Claims. (Cl. 89-198) The present invention relates to liquid spring buffers for automatic fire arms and has the following main objects:

Providing a butter insensitive to diminutions in temperature and leakage losses of spring liquid, and requiring no servicing over prolonged periods of operation.

The specific nature of the invention as well as other objects and advantages thereof will clearly appear from a description of a preferred embodiment as shown in the accompanying drawing, in which:

The drawing is a longitudinal section of a liquid spring with associated compensating reservoir.

According to the drawing, the main reservoir 1 and the compensating reservoir 2 are accommodatedin a common casing, and are separated by a partition Wall a. The plunger 5, the piston rod 6 of which projects from the casing, is exposed at any time to an impact and is guided in a bore 3 of the main reservoir. The main reservoir 1 is in communication with the compensating reservoir 2 through a bore 7 and a non-return valve 13 in the partition wall 4 of the casing. The bore 7 widens in the direction of the main reservoir to a valve seat 11 of the relief valve 13. The valved body 8 which belongs also to the non-return valve 13 is arranged between the valve seat 11 and the main reservoir. At the bottom 12 of the compensating reservoir a container 9 is attached which is expansible mainly in its longitudinal direction and which is sealed in a gas-tight manner. This container consists of a corrugated tube, i.e. a metal bellows having corrugated resilient side-walls, and is filled through a non-return valve with a highly compressed gas, for example compressed air. The main reservoir 1 as well as the space of the compensating reservoir 2 surrounding the gas container 9 contains a resilient liquid, for example a liquid silicone, which owing to its comparatively high compressibility can take in a large amount of energy.

Instead of a container 9 of corrugated tubing obviously any other suitable expansible pressure container may be used.

The non-return valve 13 prevents on one hand the supply of resilient liquid from the main reservoir to the compensating reservoir and facilitates on the other hand the supply in the opposite direction.

The pressure pulses occurring in the main reservoir during the cushioning can propagate themselves through a'non-return valve 13 not at all into the compensating reservoir 2. In this way the non-return valve 13 protects the compensating reservoir and the parts which 2,973,694 Patented Mar. 7, 1961 are present therein from extremely high pressures. Upon leakage losses the pressure gas container 9 expands a corresponding volume difference, and thereby forces liquid from the compensating reservoir into the main reservoir until the pressure in these two reservoirs 1 and 2 is equalised. Likewise a contraction of and pressure drop occurring in the liquid owing to cooling down is compensated for to a practicallysufiicient extent by the expansion of the pressure gas container 9, which is accompanied by a comparatively small Pressure drop of its content.

While we have described herein and illustrated in the accompanying drawings what may be considered a typical and particularly useful embodiment of our said invention we wish it to be understood that we do not limit ourselves to the particular details and dimensions described and illustrated, for obvious modifications will occur to a person skilled in the art.

What we claim as our invention and desire to secure by Letters Patent, is:

1. A liquid resilient buffer for an automatic fire-arm comprising in combination, a main reservoir containing a resilient liquid under pressure, a plunger movable axially in said main reservoir and fixedly connected to a piston rod extending from said main reservoir, a compensating reservoir also containing a resilient liquid, valve means connecting said two reservoirs, said valve means comprising a valve seat and a valve body, said valve body being situated between said valve seat and said main reservoir to prevent the flow of resilient liquid from said main reservoir to said compensating reservoir and to permit flow in the opposite direction and 'an expansible pressure container containing a compressed gas, to compensate any pressure loss of said resilient liquid in said main reservoir from said compensating reservoir.

2. A liquid resilient buffer for an automatic fire-arm comprising in combination, a main reservoir containing a liquid silicone under pressure, a plunger movable axially in said main reservoir and fixedly connected to a piston rod extending from said main reservoir, a compensating reservoir also containing liquid silicone, valve means connecting said two reservoirs, said valve means comprising a valve seat and a valve body, said valve body being situated between said valve seat and said main reservoir, to prevent the flow of said liquid silicone from said main reservoir to said compensating reservoir and to permit flow in the opposite direction and an expansible metal bellows having corrugated resilient side walls containing a compressed gas to compensate any pressure loss of said liquid silicone in said main reservoir from said compensating reservoir.

References Cited in the file of this patent UNITED STATES PATENTS 2,334,708 Joy Nov. 23, 1943 2,842,356 Taylor July 8, 1958 FOREIGN PATENTS 319,617 France July 26, 1902 735,887 Germany May 31, 1943 1,132,801 France Nov. 5, 1956 

